In the past days the change of a ground water in an excavation construction was not considered seriously. But recently much effort to keep the original height of the ground water from changing is being done during excavation. The reason to keep the or...
In the past days the change of a ground water in an excavation construction was not considered seriously. But recently much effort to keep the original height of the ground water from changing is being done during excavation. The reason to keep the original height of the ground water is to restrain the ground settlement which results in as cracks on roads and of buildings due to increase of effective stress with leaking of ground water through the earth retaining wall during excavation. During excavation, to prevent the ground water from leaking through retaining wall, Waterproof Method is applied in the rear of the retaining wall or the wall is used as a Waterproof wall. Waterproof Method is classified into direct setting, the column wall and the injection method, once direct setting and the column wall have been mainly used. But, the injection method which has less noise, vibration and much workability is likely to be used gradually at recent. there are few design and construction criteria for waterproof wall suitable to domestic situation. This study is aimed to find the merits and faults of water-proof method and to help the proper selection of method by analyzing construction efficiency and cost-effectiveness on various ground condition. On the result of analyzing, ground improvement method by injection was good at water-proof and construction in cohesionless soil ground. But, because groutability is not good in cohesion soil, efficiency of the inection method decreases. Micro-cement developed lately or low-visco fluid type injection material have better groutability than previous injection material. Although it could be used extensively on general ground, efficiency of water-proof is not good in cohesion soil. Based on the analysis of the characteristics and economic advantages of waterproof wall, the design and construction method of waterproof wall that is suitable to domestic situation is investigated. In design criteria, the stability analysis of the earth retaining wall, how to determine the thickness and arrangement of waterproof wall and deciding the quantity of grouting were examined. Especially, it is questionable in domestic that how to evaluate the water pressure applied to the earth retaining wall when waterproof method is used, and elasto-plastic analysis programs used in domestic do not sufficiently analyse the various factors affecting the stability of the earth retaining wall according to the change of the level of water surface. This study introduces the proper analysis method and the way in which mechanical properties is evaluated. Moreover, this study, for the quality of waterproof wall, presents the test method performed before and after construction and quality control way.